Transparent polyblends

Abstract

The polyblend comprises: (A) a graft copolymer having superstrate copolymers of monovinylidene aromatic and ethylenically unsaturated nitrile monomers and a substrate of a diene rubber dispersed in a matrix phase (B) comprising a blend of about 45 to 75 percent by weight of a (I) copolymer of monovinylidene aromatic and ethylenically unsaturated nitrile monomers and about 25 to 55 percent by weight (II) a methylmethacrylate polymer.

What is claimed is: 
     
       1. A transparent polyblend composition having: A. a graft copolymer having a graftable rubber substrate containing a diene rubber forming monomer and a superstrate of a copolymer consisting essentially of a monovinylidene aromatic monomer and an ethylenically unsaturated nitrile monomer, said graft copolymer having an average clustered particle size diameter of 0.10 to 0.70 microns and a superstrate to substrate ratio of 20 to 100:100, said superstrate copolymer consisting essentially of about 70 to 82 percent by weight monovinylidene aromatic monomer and from about 18 to 30 percent by weight of ethylenically unsaturated nitrile monomer, said graft copolymer being dispersed in   B. a matrix phase consisting essentially of a blend of about 45 to 75 percent by weight of (I) a copolymer of about 70 to 82 percent by weight of monovinylidene aromatic monomer and about 18 to 30 percent by weight of a unsaturated nitrile monomer and about 25 to 55 percent by weight of (II) a methylmethacrylate polymer.   
     
     
       2. A composition of claim 1, wherein said monovinylidiene aromatic monomer is styrene and said ethylenically unsaturated nitrile is acrylonitrile. 
     
     
       3. A composition of claim 1, wherein the rubber substrate comprises at least about 70 percent by weight of a 1,3 conjugated diene monomer and from about 0 to 30 percent by weight of a monovinylidene aromatic monomer. 
     
     
       4. A composition of claim 3, wherein said diene monomer is butadiene and said monovinylidene aromatic monomer is styrene. 
     
     
       5. A composition of claim 1, wherein said rubber substrate comprises at least about 70 percent by weight of a 1,3 butadiene conjugated diene monomer and from 1 to 30 percent by weight of an ethylenically unsaturated nitrile monomer. 
     
     
       6. A composition of claim 5, wherein said diene monomer is butadiene and said nitrile monomer is acrylonitrile. 
     
     
       7. A composition of claim 1, wherein the refractive index of matrix phase (B) matches that of the graft copolymer phase (A) such that the polyblend is transparent. 
     
     
       8. A composition of claim 1, wherein the rubber moiety of said graft copolymer (A) is present in said polyblend in amounts of from about 2 to 35 percent by weight of said polyblend. 
     
     
       9. A composition of claim 1, wherein said methylmethacrylate polymer is a copolymer of methylmethacrylate and a comonomer selection from the group consisting of ethyl methacrylate, propyl methacrylate, butyl methacrylate, amyl methacrylate and hexyl methacrylate or mixtures thereof. 
     
     
       10. A process for preparing transparent polyblends comprising dry blending A. a graft copolymer having a graftable rubber substrate containing a diene rubber forming monomer and a superstrate of a copolymer comprising a monovinylidiene aromatic monomer and an ethylenically unsaturated nitrile monomer, said graft copolymer having an average clustered particle size diameter of 0.10 to 0.70 microns and a superstrate to substrate ratio of 20 to 100:100, said superstrate copolymer comprising about 73 to 82 percent by weight monovinylidene aromatic monomer and from about 18 to 27 percent by weight of ethylenically unsaturated nitrile monomer, with   B. a matrix phase comprising a blend of about 45 to 75 percent by weight of (I) a copolymer of about 73 to 82 percent by weight of monovinylidene aromatic monomer and about 18 to 27 percent by weight of a unsaturated nitrile monomer and about 25 to 55 percent by weight of (II) a methylmethacrylate polymer followed by melt colloiding the dry blend of (A) and (B) at temperatures of from about 150° to 250° C. forming a uniform polyblend.   
     
     
       11. A process of claim 10, wherein said monovinylidiene aromatic monomer is styrene and said ethylenically unsaturated nitrile is acrylonitrile. 
     
     
       12. A process of claim 10, wherein the rubber substrate comprises at least about 70 percent by weight of a 1,3 conjugated diene monomer and from about 0 to 30 percent by weight of a monovinylidene aromatic monomer. 
     
     
       13. A process of claim 10, wherein said diene monomer is butadiene and said monovinylidene aromatic monomer is styrene. 
     
     
       14. A process of claim 10, wherein said rubber substrate comprises at least about 70 percent by weight of a 1,3 butadiene conjugated diene monomer and from 1 to 30 percent by weight of an ethylenically unsaturated nitrile monomer. 
     
     
       15. A process of claim 10, wherein said diene monomer is butadiene and said nitrile monomer is acrylonitrile. 
     
     
       16. A process of claim 10, wherein the rubber moiety of said graft copolymer (A) is present in said polyblend in amounts of from about 2 to 35 percent by weight of said polyblend. 
     
     
       17. A process of claim 10, wherein said methylmethacrylate polymer is a copolymer of methmethacrylate and a comonomer selected from the group consisting of ethyl methyacrylate, propyl methacrylate, butyl methacrylate, amyl methacrylate and hexyl methacrylate or mixtures thereof. 
     
     
       18. A process of claim 10, wherein the refractive index of the matrix phase (B) matches that of the graft copolymer (A) such that the polyblend is transparent. 
     
     
       19. A process of claim 10, wherein said methylmethacrylate polymer is a polymethylmethacrylate homopolymer. 
     
     
       20. A composition of claim 1, wherein said methlmethacrylate polymer is a polymethylmethacrylate homopolymer.